Insulator clamping device



March 1, 1955 w. L. SCOTT, JR

INSULATOR CLAMPING DEVICE Filed July 21, 1945 United States PatentINSULATOR CLAMPING DEVICE William L. Scott, 511., Oak Ridge, Tenn.,assiguor, by mesne assignments, to the United States of America asrepresented by the United States Atomic Energy Commission ApplicationJuly 21, 1945, Serial No. 606,405

6 Claims. (Cl. 174--163) This invention relates to a supporting devicefor members such as insulators or the like which are exposed to arelatively wide range of temperature. Insulators are often made ofceramic materials or other materials having like characteristics whichhave a different temperature coefiicient of expansion than metals fromwhich supporting devices are ordinarily made. The insulators must befirmly supported, that is clamped, or gripped at ordinary temperaturesand must be similarly firmly supported, often at considerably highertemperatures. The arrangement must be such that at rising temperaturesthe supporting means continues to firmly support the insulating memberbut without producing so much stress therein as to fracture, deform, ormisalign the insulator.

This is particularly important in some types of apparatus whereininsulating members constitute the supporting means for electrodes orother elements which must be maintained in very accurate alignment overa considerable range of temperature and at times also while under theinfluence of a strong magnetic field. An object of my invention istherefore to provide supporting means for an insulator or the like whichwill firmly support the insulator over a wide range of temperaturewithout allowing the insulating member to become loose and withoutapplying excess force such as to produce stresses which might fracture,deform or misalign the insulator.

Another object of the invention is to provide supporting means for aninsulator or the like comprising a clamping arrangement formed ofmaterial having a different coefficient of expansion than material ofthe insulator and embodying a resiliently deformable member so arrangedthat upon rising temperature the resiliently deformable membercompensates for the different expansion in the clamping means than inthe material of the insulator.

Another object of the invention is to provide supporting means forinsulators or the like comprising a clamp ing device so arranged that apart thereof is under spring tension when in clamping position and sothat upon rising temperature, even though the clampingdevice expands ata different rate than the material of the insulator, the spring tensionis such as to cause the insulator to be firmly clamped.

Another object of the invention is to provide supporting means for aninsulator or the like comprising resiliently deformable clamping membersarranged to be clamped against the insulator and placed under springtension and so arranged that the clampmg forcels substantially the sameover a wide range of temperature even though the material of theclamping members expands at a different rate than the material of theinsulator.

Another object is to provide an arrangement as in the preceding objectwherein the clamping members are arcuate and have such a radius ofcurvature as to normally engage the insulator at their ends.

Another object or" the invention is to provide supporting means for aninsulator or the like comprising deformable clamping members arranged tobe clamped against the insulator, the ends of the members frictionallyengaging the insulator to permit free thermal expansioncircumferentially of the insulator.

Another object is to provide an insulator and clamping members as in theprevious obiects wherein the insulator and clamping members havemutually engaging surfaces so shaped as to prevent lateral displacementof the members along the insulator.

Further objects and numerous of the advantages of 7 described.

my invention will become apparent from the following detaileddescription and annexed drawings wherein:

Fig. l is a view partly in cross section of an insulator supported bythe improved supporting means of my inventlon.

Fig. 2 is a view partly in section taken 2-2 of Fig. 1.

Fig. 3 is a plan view of a detail of Fig. line 3-3 of Fig. 1.

Referring to the drawings, numeral 10 designates an insulator orinsulating member of standard type fluted construction which issupported in the improved manner of my invention. The insulator 10extends outwardly from a metal plate 11 to which it is attached as willbe Numeral 12 designates a shield which is around the insulator andwhich is attached to the plate 11 by soldering as shown. The shield12forms a protective device for the insulator to protect it frombombarding particles and it has a continuous head 13 attached to itsouter edge, the purpose being to eliminate sharp edges which areconducive to electrical arcing.

Numeral 16 designates a plurality of lugs, of which there are three,which are soldered to the plate 11 and to the shield 12 in a circlespaced at intervals as may be seen on Fig. 2. The lugs 16 arerectilinear in shape and to each of them is attached a clamping element17 which clamps the insulator 10. The left end of the insulator 10 iscircular but its conformation is such as to form two oppositely taperingsurfaces as shown in cross-section on Fig. 1. Each of the clampingelements 17 has a groove at its upper part as shown on Fig. l in whichengages a shoulder or rib on the lugs 16, the mutually engaging parts ofthe elements 17 and the lugs 16 being convex and concave respectively.Numeral 20 designates set screws which extend inwardly through the lugs16 and which are adjustable through openings in the shield 12, the setscrews bearing against the elements 17 whereby the said elements can beadjusted or forced inwardly, that is, radially against the insulator 10.The elements 17 are concave on their inner sides and they haveoppositely tapering surfaces as shown on Fig. l which match the taperingsurfaces on the insulator lit and mutually engage therewith. However,the radius of curvature of elements 17 is slightly smaller than theradius of curvature at the left end of the insulator 10 so that thecontour of the elements 17 does not conform exactly to the surface ofthe insulator 10 as may be seen at Fig. 2. Each of the elements 17 has acentral depression on its concave side as may be seen on Fig. l, theelements 17 being somewhat greater in extent circumferentially of theinsulator than the lugs 16 as may be seen on Fig. 2.

From the foregoing it will be observed that by tightening up on the setscrews 20 the elements 17 are caused to hear tightly against thetapering surfaces of the in sulator 10 thus placing the elements 17under spring tension, these elements being resiliently deformable. Theforce exerted by the elements 17 to clamp. or grip the insulator 10 ofcourse depends .upon the amount of spring tension on the elements 17 asdeveloped by tightening up on the set screws 20. Elements 17 areconstructed, for instance, of spring steel or other suitable materialhaving a resilient characteristic, and are designed, as to dimensions,such that they may be deformed through the necessary range of operationwithout breaking. The oppositely tapering matching surfaces preventmovement to right or left of the insulator when it is in clampedposition. Upon rising temperature in the vicinity of the insulator, thematerial of the clamping members that is the elements 17 and the lugs 16and the set screws will expand faster than the material of the insulatorwhich may be of ceramic for example. Thus due to the radial expansion ofthe lugs 16 and the elements 17 the tendency will ordinarily be to clampor grip the insulator more firmly, the expansion of plate 11 not beingappreciable; however, there will also be lateral expansion of theelement 17 relatively to the insulator and, due to the fact that theseelements are resilient and under spring tension, further deformation ofthem is permitted and their normal contour tends to conform more nearlyto the contour along the line 1 taken along or surface of the insulator10. The effect is that as the temperature rises the insulator is clampedor gripped with substantially the same force by the clamping elements17. To explain this effect more specifically, if the temperature rises,due to the longitudinal expansion of lug 16 and set screw 20, thedistance between the insulator 10 and the point of engagement of lug 16and clamping element 17 decreases. If the normal (undeformed) contour ofclamping element 17 were to remain the same, there would thus result agreater deformation of clamping element 17 from its normal contour, andtherefore a greater clamping force upon the insulator. However, as thetemperature rises, there is a simultaneous straightening out of theclamping member 17 with the result that it acquires a new normal contourcorresponding to the new higher temperature, this new normal contourconforming more closely to that of the adjacent surface of theinsulator, and decreasing that amount of deformation of the clampingelement from its normal contour which corresponds to any particulardistance between the insulator and the point of engagement of lug 16 andclamping element 17. Thus, if this latter distance remained the same,the deformation of clamping element 17, and the clamping force upon theinsulator, would both decrease. Thus there are two mutually opDosingeffects accompanying any temperature change. The resiliency of clampingelement 17 is made by design just sufficient, taking into considerationthe dimension and temperature coetficients of expansion of the variousassociated portions of the device, for these mutually opposing effectsto substantially cancel each other out, whereby the insulator is alwaysretained by the clamping elements with substantially constant force. Theinsulator is thus held firmly at all temperatures without misalignmentand stresses are not developed such as to be so excessive as tofracture, deform or misalign the insulator itself. The spring tension inelements 17 compensates for any relative changes in dimensions of partscaused by temperature changes.

From the foregoing those skilled in the art will observe that I haveprovided an efficient and simple device whereby insulators and the likemay be firmly supported and subjected to a wide range of temperaturewithout loss of support and without danger of fracturing or otherwisebreaking the insulator or deforming it or forcing it out of its properoriginal alignment.

I claim:

l. In a support for insulatorsand the like, in combination, meanscomprising at least one resiliently deformable clamping member forholding the insulator, and means associated with the clamping member fordeforming it to apply a spring force against the insulator, said clamping member being arcuate and having a radius of curvature less than thatof an adjacent portion of said insulator, whereby only its opposite endsnormally engage the insulator.

2. In a support for insulators and the like, in combination, at leastone arcuate resiliently deformable clamping member having a radius ofcurvature less than that of an adjacent portion of said insulator,whereby opposite ends thereof are adapted to bear against the insulatorportion, and means associated with said clamping member for applying aninwardly directed radial deforming force against said clamping member,whereby said insulator is held in place by the spring force exerted bysaid endsresulting from the deformation of said clamping member.

3. In a support for insulators and the like, in combination, at leastone arcuate resiliently deformable clamping member having a radius ofcurvature less than that of. an adjacent portion of said insulator,whereby opposite ends thereof are adapted to bear against the insulatorportion, and adjustable means, including an externally adjustable screwelement, associated with said clamping member for applying an inwardlydirected radial deforming force against said clamping member, wherebysaid insulator is held in place by the spring force exerted by said endsresulting from the deformation of said clamping member.

4. In a support for insulators and the like, in combina tion, at leastone arcuate resiliently deformable clamping member having a radius ofcurvature less than that of an adjacent portion of said insulator,whereby opposite ends thereof are adapted to bear against the insulatorportion, and means associated with said clamping memher for applying aninwardly directed radial deforming force against the center of saidclamping member, whereby said insulator is held in place by the springforce exerted by said ends resulting from the deformation of saidclamping member.

5. In a support for insulators and the like, in combination, at leastone arcuate resiliently deformable clamping member having a radius ofcurvature less than that of an adjacent portion of said insulator,whereby opposite ends thereof are adapted to bear against the insulatorportion, a fixed lug element adjacent the center of said clamping memberon its outer side, said lug element having a tapped hole therethroughterminating at the center'of said clamping member, and an adjustablescrew element associated with said lug element and bearing against thecenter of said clamping member for applying an inwardly directed radialdeforming force against said clamping member, whereby said insulator isheld in place by the spring force exerted by said ends resulting fromthe deformation of said clamping member.

6. In a support for insulators and the like, in combination, at leastone arcuate resiliently deformable clamping member having a radius ofcurvature less than that of an adjacent portion of said insulator,whereby opposite ends thereof are adapted to bear against the insulatorportion, said clamping member having a V- shaped cross sectionconforming to a similarly shaped cross section of the adjacent portionof the insulator, and means associated with said clamping member forapplying an inwardly directed radial deforming force against saidclamping member, whereby said insulator is held in place by the springforce exerted by said ends resulting from the deformation of saidclamping member.

References Cited in the file of this patent UNITED STATES PATENTS1,070,151 Martin Aug. 12, 1913 1,574,964 Getts Mar. 2, 1926 1,831,798Alsaker Nov. 17, 1931 2,179,406 Fitzpatrick Nov. 6, 1939 FOREIGN PATENTS4,075 Great Britain of 1904 104,177 Great Britain Nov. 8, 1917 360,059Great Britain Nov. 5, 1931

